In any given battle in The Witcher, the object is for Geralt to win, either by killing or frightening off his foes. This is achieved by inflicting as much damage on opponents while taking as little damage from them as possible. The damage inflicted can be enhanced positively (for Geralt) by making use of weapons and signs which increase the critical effects that some of these possess. The damage can also be negatively enhanced (i.e. be more damaging to Geralt) as well, if his opponents possess weapons of their own which enhance some critical effects.
Attack: The chance of successful attack. The higher the attack, the smaller the probability of enemy evading the attack.
Dodge: Chance of evading / avoiding enemy attacks. Most effective against monsters whose attacks can not be parried.
Parry: Chance of blocking enemy blows. Most effective against armed opponents.